The field of the invention is automated processing systems used for processing semiconductor wafers, hard disk media, semiconductor substrates, and similar articles requiring very low levels of contamination.
Computers, televisions, telephones and other electronic products contain large numbers of essential electronic semiconductor devices. To produce electronic products, hundreds or thousands of semiconductor devices are manufactured in a very small space, using lithography techniques on semiconductor substrates, such as on silicon wafers. Due to the extremely small dimensions involved in manufacturing semiconductor devices, contaminants on the semiconductor substrate material, such as particles of dust, dirt, paint, metal, etc. lead to defects in the end products.
To exclude contaminants, semiconductor substrates and similar articles are processed within clean rooms. Clean rooms are enclosed areas or rooms within a semiconductor manufacturing facility, designed to keep out contaminants. All air provided to a clean room is typically highly filtered to prevent airborne contaminants from entering into or circulating within the clean room. Special materials and equipment are needed to maintain contaminants within the clean room at adequately low levels. Consequently, construction and maintenance of clean rooms can be time consuming and costly. As a result, the semiconductor processing equipment installed within a clean room should preferably be compact, so that large numbers of semiconductor wafers can be processed within a smaller space, thereby reducing space requirements and costs. Accordingly, there is a need for smaller semiconductor processing equipment, to reduce clean room space requirements.
Existing automated semiconductor processing systems use robots to carry the semiconductor materials. These robots are designed to avoid creating particles which could contaminate the semiconductors. However, even with careful design, material selection, and robot operation, particles may still be created by these robots, via their moving parts. Accordingly, there is a need for improved techniques for processing articles with very low levels of contamination to maintain the level of defects at acceptable levels.
In a first aspect of the invention, an automated processing system has an indexer bay or space and a process bay or space within an enclosure. The indexer bay is oriented perpendicularly to the process bay, to form a compact design requiring less floor space in a clean room.
In a second separate aspect of the invention, an indexer is provided in the indexer bay. The indexer preferably holds pallets for supporting articles contained within cassettes. Pallet movers in the indexer move the pallets and cassettes in sequence from an indexer loading position, through a plurality of intermediate storage positions, to an indexer unload position. The indexer allows the automated processing system to run continuously, by moving and storing cassettes.
In a third separate aspect of the invention, a process robot within an automated processing system has a robot arm vertically moveable along a lift rail. The robot arm has a forearm segment extending between an elbow joint and a wrist joint. A wafer holder on the robot arm is laterally offset from the elbow and wrist joints. The robot arm is compact yet has an extended range of travel. The processing system therefore requires less space.
In a fourth and separate aspect of the invention, a moveable buffer shelf is positioned over the indexer, to increase productivity and versatility of the system.
In a fifth and separate aspect of the invention, a novel process module door is provided to better close and seal a process module chamber.
In a sixth aspect of the invention, two or more of the features described above are combined to provide an improved automated processing system.
It is an object of the invention to provide an automated processing system, better designed to keep articles free of contaminants. It is a further object of the invention to provide an automated processing system that is versatile, yet compact, to reduce clean room space requirements.
Other objects, features and advantages will appear hereinafter.